My MM had worn out the shaft hole on the last gear of the castle gate drive
train. Not available as far as we can tell, so we made another out of Delrin.
These parts are laser cut; the tooth design holds up reasonably well, despite
the laser kerf. We made two and sandwiched them together to get the right shaft
catch. The original uses a cluster gear, but the smaller gear is unused.

Delrin is hard to glue, so the parts are held together with dowel pins and
cyaonacrylate.

The replacement gear works perfectly. I figure that I can probably do the
gear clusters with a small hub by using smaller pins. Therefore, we should be
able to reproduce most pinball gears.